Electrical insulator



Aug. 11, 1936. H. P. SEELYE ELECTRICAL INSULATOR Filed June 22 1955Patented Aug. 11, 1936 2,050,898

UNITED STATES PATENT OFFICE ELECTRICAL INSULATOR Howard P. Seelye, RoyalOak, Mich.

Application June 22, 1933, Serial No. 677,113

9 Claims. (Cl. 173-321) This invention relates to improvements in elecpuOut Of the insulating p during the trical insulators of the single knobtype which twisting movement of installation. form the support for oneor more electric wires Anether O j ct of y v on s to s fasten or cables.Such devices are in wide use where the screw in the Porcelain p that thep is electric wiring is supported from cross arms, ve y distributedentirely heroes the base of 5 brackets, posts or the exterior ofbuildings. The the letter and insures servieeebility 1 t0 the conductorsare mounted on such insulators either limit 0f the strength of theporcelain e Which at an intermediate point or the end of a stretch theinsulating p is C st ucted. of wire. In either .event the insulators arein A further Obje t O my invention is to provide tended to withstand thestresses imposed by the e fastening between the screw and the insulat-10 tension of the wiring. The wiring may thus be illg p which by reasonof its mode of pp carried ar u d corner or h 1 by th end of tion tendsto provide a thoroughly reliable firm its length from the support. Inthe latter ina e t b w the p stance this condition is referred to asdead other Objects of y inventi0n Will be found ending d th full tensionof t length of t to follow from the specific characteristics of the 15wire is applied to the insulator in a sin le didevice as illustrated inthe a p yin drawrection. Insulators of this type must, therefore, inwhich,

be able to withstand the stress imposed by the e 1 is a side elevationof the insulator; weight and the tension of a line of wire regard- Fig.2 is a Vertical Section 011 the line 0f less of the direction in whichthis stress is 20 applied, Fig. 3 is a vertical elevation on the line3-3 of To meet these situations, insulators must be and of simple, cheapand rugged construction so 4 is a bottom V w P y in ction. I that theycan be affixed in position by the line- As illustrating the preferredform and the men without the use of e i l t l or h essential features ofmy invention, I have shown 25 exertion of undue force. In service thedevices y y Of eXemDIe an insulating b b 01 must be inherently capableof withstanding the the like This knob is generally yl d ical instresses produced. form and has a fiat circular base 6. The upper It isa prime consideration in such insulators portion 7 0f the knob isgrooved t0 D Vide tWO that the fastening members such as wood screws, ormore heads 8 by which the electrical pa of 30 bolts or the like shall befirmly held by the leakage is increased a d greater ac y P insulatingpart but at the same time removed Vided di t -W res.

as far as possible from the wire-attaching part The upper end of t b 5es a Saddle sothat the electrical path of leakage is as great 9 which isalso customary for dat g 5 as possible. either the electric wires to besupported or the The best and most commonly used material tie-Wiresthereforfor the insulating knobs of this type is porce- A centralopening It f s a passageway lain. However, it is not feasible to apply ametransversely through he upp p 1 f he tallic wood screw or otherfastening directly to knob and is adapted to receive the electrical theporcelain itself during manufacture since if conductor or Wire and topermit the latter to be 40 the screw is molded in the plastic porcelainand j up to insulator from any direction the latter then fired, thetemper of the steel in Wlthout meetmg sharp edges the screw is drawn,the screw is deformed and Thepase 6 of the knob has recess H extend theshrinkage during drying of the porcelain remg axially from} the but notas far sults in separation from the screw. Imbedding ig ifi g ifi g g'2: #5 5? jg q' 45 s is 25555125; 1 ;ggifi i gg sfii z iz i gi 3;extended or flattened as more clearly illustrated in Figs. 2 and 4.fastening substance may disintegrate and it is The central portion ofthe recess has an diflicult to design a screw-head which willwithlargement of circular cross section fo 50 stand torsion. grooves I2in the side walls for the purposes of y p v deslgh as here described p tguiding and centering the shank of the screw. the assembly i a mp dcheap manner f This screw has been illustrated as a wood t fasteningmeans in t e i sulating member screw l3 although a machine bolt, lagscrew or 5,5; so that there can be no possibility of the screw the likecan also be used as circumstances may dictate. The screw i3 is of thetype which can be threaded into wood without previously boring a hole.The shank H5 of the screw is generally cylindrical and terminates in aflattened eye 15. This eye l5 conforms closely to the cross-sectionadopted for the recess M in which latter it is positioned as shown inthe drawing. The eye extends near the top of the recess but not incontact therewith so that its ultimate position will be determined bythe fastening means.

The fastening means consists of a transverse bolt it. This bolt is inthe form of a rod of copper or like material having a flaring head H anda hollow opposite end l8 normally of the same diameter of the bolt it.This bolt serves as a rivet and the end l8 can be swagedor upset tocompress the rivet and cause the metal thereof to flow laterally. I

A passageway 59 is provided in a lower portion of the insulating knob 5and is preferably arranged in a direction perpendicular to the axis ofthe opening ill. The ends of the passageway B9 are counter-sunk orflared as clearly shown in Fig. 3. The passageway i9 is only largeenough to permit insertion of the rivet I5 so that the headil will restagainst one opening it and the opposite end it can be flared by swagingor upsetting to engage the opposite opening 2?].

The insulator as above outlined permits the assembly of fastening meansto an insulator knob of porcelain or analogous pre-formed material.

In making the insulator the eye 15 of the screw-eye i3 is inserted inthe recess l l with the opening of the eye in registry with thetransverse passageway lQ.

In the course of this movement the cylindrical shank M is guided andcentered by the grooves l2, l2 so that the screw-eye I3 will extend in adirection perpendicular to the plane of the base 6. The rivet i6 is thenpassed transversely of the passageway l9 and through the eye of thescrew-eye. A simple upsetting or swaging operation serves to compressthe rivet it so that the end 88 is spread and the rivet prevented fromendwise movement. At the same time the metal of the rivet i6 is causedto flow to an extent sufiicient to completely fill the passageway 89 andthe eye l5. At the same time the shank M is held by the grooves l2, 112.It follows that the screw cannot rock out of its position perpendicularto the plane of the base 6 and further that the engagement between theeye 85 and the rivet i6 is such as to prevent the screweye 53 frombecoming loose or from being pulled out of the knob 5.

Even greater strength may be given this fastening by filling the recessH and the intersecting parts of the screw-eye l3 and rivet it by meansof a substance which will anchor the parts together and extend the areaof contact with the knob 5. One such means is molten lead which can bepoured down around the screw and into the various crevices around it andalso around the intersecting cross-pin. This provides a form of cushionand evens or distributes the strain. Other forms of cement or anchoringsubstances are equally effective.

The knob so assembled may be attached to any convenient support bymanual force. The screw it can be started into the wood of the supportby a light blow after which the knob forms a convenient handle by whichthe screw may be twisted and thus drawn up until the base 6 is incontact with the surface of the support.

The heads ll and E8 of the rivet are countersunk beneath the surface ofthe knob 5 and on a line circumferentially spaced from the ends of bore[9 and may if desired be covered with insulating cement or othermaterial so that the path of leakage is further obstructed. The rivet l6extending diametrically across the knob provides for the distribution ofany strain that may be imposed during the twisting of the knob. At thesame time the lateral extension of the recess H to accommodate the eyel5 permits the latter to have an extended bearing in the knob 5 and thusminimize torsional strain. This cushioning effect is even greater whenlead or other cement is poured into the recess around the screw-eyeandcross-pin as above described.

While I have illustrated the preferred form of the device'for thepurpose of example, there are many changes in details and arrangementswhich are within the scope of the invention defined in the followingclaims.

What I claim is:

1. In an insulator, an insulating member havan upper transversewire-receiving opening, a. rectangular recess axially through the baseof the member, a lower transverse passageway intersecting the recess, ascrew-eye having a flattened eye positioned in the recess and inextended contact with the side walls of the latter, and a member in thepassageway passing through the eye of said screw-eye. 2. In aninsulator, an insulating member having an upper transversewire-receiving opening, a rectangular recess axially through the base ofthe member, a lower transverse passageway intersecting the recess, ascrew-eye having a flattened eye positioned in the recess and inextended contact with the side walls of the latter, and a rivet throughthe passageway and the eye of the screw-eye and upset.

3. In an insulator, an insulating member having an upper transversewire-receiving opening, a laterally extended recess axially through thebase of the member, a lower transverse passageway intersecting therecess, a screw-eye having a flattened eye positioned in the recess andin extended contact with the side walls of the latter, and a member inthe passageway, passing through the eye of said screw-eye.

4. In an insulator, an insulating member having an upper transversewire-receiving opening, an axial recess through the base of the member,guide grooves in said recess, a lower transverse passageway intersectingthe recess, a shouldered screw-eye and a member in the passageway anddrawing the shoulder of the screw-eye into said guide grooves.

5. In an insulator, an insulating member having an upper transversewire-receiving opening, an axial recess through the base of the member,a lower transverse passageway intersecting the recess, a screw-eye inthe recess and a deformable rivet in the passageway and passing throughthe eye of said screw-eye.

6. In an insulator, an insulating member having an upper transversewire-receiving opening, a recess through the base of the member, saidrecess being oblong in cross-section, a groove extending axially of themember centrally of each long side of said recess, a lower transversepassageway intersecting the recess in the same plane with said grooves,a screw-eye in the recess and a deformable rivet in the passageway 7'5and passing through the eye of said screw-eye.

7. In an insulator, an insulating member having an axial recess throughthe base thereof, a transverse passageway intersecting the recess, ascrew-eye in the recess, a member passing through said screw-eye, andanchoring means in the recess around said screw-eye and member.

8. In an insulator, an insulating member having an upper transversewire-receiving opening, a laterally extended recess axially through thebase of the member, axial guide grooves in said recess, a lowertransverse passageway intersecting the recess centrally thereof, ashouldered screw-eye and a member in the passageway passing centrallythrough the screw-eye and drawing the sides of the latter into extendedtorsional contact with the walls of the recess around the said lowertransverse passageway.

9. In an insulator, an insulating member having wire holding means, arecess extending axially into the base of the member, said recess havingopposed parallel fiat sides, an attaching member insertible into saidrecess and having one end formed with similar opposed flat sides andmeans for holding the end of the said member in the recess with thesides of the member in extended contact with the sides of the recess.

HOWARD P. SEELYE.

